This invention relates to phase break and section insulator devices for an electrical traction system to establish electrically insulating connections of high tensile strength between two energized sections of the trolley contact wire in the traction system.
The known devices of this type, which are used as section or phase insulators between two contact wire sections ending at a distance from each other, suffer from a number of disadvantages. Their design is either relatively unstable or else complicated, difficult to assemble, expensive, heavy, and not capable of being mounted on the contact wire before this wire has been cut into two pieces in order to obtain two sections. This latter aspect makes the installation considerably more difficult because the contact wire ends which are to be joined by the section or phase insulator must then be held in the correct position by an auxiliary device. Also, if this installation method is used, it can, as a rule, not be avoided that one or several kinks are made in the contact wire to cause the current collector to lose contact with the wire at high speeds. Further, the heavy weight of certain known devices causes a shock on the current collector of the vehicle being supplied with power from the contact wire when it passes the insulator. This shock exerts a force on said collector in the direction which can cause the collector to lose contact with the wire, and mechanical damage also can result from bouncing. The force on the current collector grows with the speed of the vehicle. As it is mandatory to prevent the collector from losing contact with the wire as a result of the shock and as the maximum speed with which the collector can pass the known section and phase insulators without losing contact with the wire is only slightly above current speeds, the known section and phase insulators cannot be used for the higher speeds.
The disadvantages described above also apply to known designs of section or phase insulators which use glass fiber reinforced plastic rods as insulating elements, as these insulators, too, cannot be installed on the contact wire before this wire has been cut at the point of installation, and as they also are comparatively heavy.
Another disadvantage of known section and phase insulators is that they generally must be of different design from each other and have not been constructed of common or identical modules, the phase insulator generally having a rigid grounded center section. This creates added manufacturing and storage complexity.
Still further disadvantages of known section and phase insulators include the buildup of moisture and dirt deposits on the insulating elements to cause failure or at least periodic maintenance and cleaning.
Known section and phase insulators in addition often do not provide adequate protection of the insulating elements against damage caused by electrical arcs, and do not sufficiently extinguish arcs.